(1) Field of the Invention
The present invention relates to a tip for a tubular writing pen having a writing tube secured in a forepart that is joined to a pen body. A writing fluid conductor, having a front end in contact with the drawing surface during use, is movable in the axial direction, and extends into the writing tube. The rearward end portion of the writing fluid conductor communicates with a reservoir of writing fluid. The projecting length of the writing fluid conductor beyond the front end of the writing tube is adjustable.
(2) Brief Description of the Prior Art
In a known tubular writing pen of this type (DE-PS No. 1 274 929), the forepart carrying the writing tube is screwed into the pen body, and the writing fluid conductor comprises a cleaning wire which is secured in the front end of a falling weight body. The falling weight body is supported, at its front end, upon appropriately embodied portions of the pen body, thereby fixing the length by which the cleaning wire projects beyond the front end of the writing tube. This projecting length can be adjusted during the assembly of the tubular writing pen, or after the front end of the cleaning wire has worn down, by changing the relative position of the forepart. The forepart can be screwed into or out of the pen body, by appropriately rotating the forepart.
In this known tubular writing pen it is possible to adjust the projecting length in a simple manner. However, impact stresses on the forepart are particularly prevalent when the tubular writing pen, or its tip, is used in a plotter, because the writing tube is applied repeatedly to the drawing surface. These stresses present a danger that the location of the forepart within the pen body will shift.